Isomerization of cyclo triene compounds



United States Patent ISOMERIZATION OF CYCLO TRIENE COMPOUNDS Donald L. Crain and Howard A. Hartzfeld, Bartlesville,

Okla., assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Mar. 31, 1960, Ser. No. 18,810 23 Claims. (Cl. 260-666) This invention relates to the isomerization of cyclo triene compounds. In one aspect this invention relates to novel bicyclo diene compounds. In still another aspect this invention releates to a process for isomerizing cyclo triene compounds to bicyclo diene compounds. In still another aspect this invention relates to a novel saturated bicyclo hydrocarbon.

It has recently been disclosed by G. Wilke in Angew. Chem. 69,397-8 (1957) that butadiene can be trimerized in 80 percent yield to trans, trans, cis-l,5,9-cyclododecatriene. This trimerization is carried out by means of a catalyst system comprising an organoaluminum such as triethylaluminum in conjunction with a metal halide such as titanium tetrachloride. The cyclic triene which is formed boils at 100-101 C. at 11 mm. Hg absolute pressure. Thus, this synthesis represents a method of preparing a lZ-carbon compound from a compound of much lower molecular weight.

We have now discovered that cyclo trienes prepared by trimerizing 1,3-butadiene, or related compounds such as isoprene and piperyle'ne, can be isomerized to novel bicyclo dienes. In one specific embodiment of the invention, we have discovered that trans, trans, cis-1,5,9-cyclododecatriene can be isomerized to novel bicyclo dodecadienes. In another specific embodiment of the invention, we have discovered that said novel bicyclo dodecadienes can be hydrogenated to form a novel bicyclododecane.

Thus, broadly speaking, the present invention resides in: novel bicyclo diene compounds; methods of preparing said bicyclo diene compounds by isomerizing cyclo triene compounds; a novel bicyclododecane; and methods of preparing said bicyclododecane by hydrogenation of said novel bicyclo diene compounds.

An object of this invention is to provide novel bicyclo diene compounds. Another object of this invention is to provide a process for preparing said novel bicyclo dienes by isomerizing cyclo triene compounds. Another object of this invention is to provide a novel bicyclododecane. Still another object of this invention is to provide a process for preparing said bicyclododecane by hydrogenating said bicyclo diene compounds. Still another object of this invention is to provide a process for preparing novel bicyclo dodecadiene compounds by isomerizing trans, trans, cis-1,5,9-cyclododecatriene. Other aspects, objects and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus, according to the invention there are provided novel bicyclo hydrocarbons including the following:

Bicyclo-[5.5.0]-1,7-dodecadiene; Bicyclo-[5.5.0]-A ,2-dodecadiene; Bicyclo- [5.5.01-dodecane; and Bicyclo-[5.5.0]-trimethyldodecadiene Further according to the invention there is provided a method of isomerizing a cyclo triene hydrocarbon to bicyclo diene hydrocarbons containing the same number of carbon atoms and hydrogen atoms as the starting cyclo triene hydrocarbon, which method comprises contacting said triene with an isomerization catalyst selected from the group consisting of alkali metal amides and alkaline earth metal amides in the presence of an amine solvent which is a solvent for both said triene and said isomerization catalyst.

3,009,001 Patented Nov. 14, 1961 Still further according to the invention, there is provided a process for the preparation of bicyclo-[5.5.0]- dodecane, which process comprises: hydrogenating a bicyclo dodecadiene selected from the group consisting of bicyclo-[5.5.0]-l,7-dodecadiene, bicyclo-[5.5.0]-A -",2-dodecadiene, and mixtures thereof, in the presence of a reduced metal hydrogenation catalyst, at a temperature within the range of 0 to 200 C., and under a pressure within the range of atmospheric to 1000 p.s.i.a.; and recovering said bicyclo-[5 .5 .0] -dodecane.

Suitable isomerization catalysts which can be employed in the practice of the invention are the alkali metal amides and the alkaline earth metal amides. As used herein and in the claims, unless otherwise specified, the term alkali metals refers to and includes sodium, potassium, lithium, rubidium, and cesium; and the term alkaline earth metals refers to and includes calcium, barium, and strontium.

Examples of isomerization catalysts which can be employed in the practice of the invention can be represented by the following structural formulas:

R R R R Maha a] I l. 2

III

I II and atoms, and (c) R I L L...

radicals wherein R is as defined above, R" is an alkylene radical containing from 2 to 3 carbon atoms, y is an integer of from 1 to 2, and wherein when R' is a cycloalkylene radicaLIonly one amino nitrogen atom is attached to any one ring carbon atom.

Said isomerization catalysts employed in the practice of the invention can be prepared by any suitable method known to those skilled in the art. A number of said catalysts are commonly prepared by the direct reaction of the desired metal with ammonia or a suitable primary or secondary amine. For example, the monoamide of lithium and ethylenediamine can be prepared by contacting metallic lithium with ethylenediamine, at a temperature such as about 30-1 15 C., for a period of time suflicient to obtain reaction of said metal with said amine, generally 1 to 5 hours. One example of the preparation of said monoamide of lithium and ethylenediamine is given in Example I below. The monoamides, of potassium, rubidium, and cesium can be prepared in a manner similar to that for said monoamide of lithium and ethylenediamine. The' amides of sodium, calcium, strontium, and barium of Formula I or II and the alkyl substituted amides of Formula III or IV can be prepared by the reaction of the desired amine with the inorganic amides, i.e., sodium amide, calcium amide, strontium amide, and barium amide, all of which compounds are available commercially or can be readily prepared by known methods. Said amide catalysts can be prepared in situ in the reaction vessel or they can be prepared ahead of time, stored until needed (preferably under an atmosphere of nitrogen), and then dissolved in the amine solvent to be employed in the isomerization reaction when needed. Examples of the metal amides which fall within the scope of the above general formulas are the lithium, potassium, sodium, rubidium, cesium, calcium, strontium and barium amides of the following amines, among others: ethane-1,2- diamine; propane-1,3-diamine; propane-1,2-diamine; cyc1ohexane-1,2-diamine; cyclohexane 1,4 diamine; 4- methylcyclohexane-1,2-diamine; 5,6 diethyleyclohexanel,3-.diamine; 3-n-butylcyclohexane-1,2 diamine; diethylenetriamine; dipropylenetriamine; triethylenetetraamine; methylamine; diethylamine; n-propylamine; di-n-butylamine; di-n-hexylamine; sec-octylamine; and di-n-decylamine.

The monolithium amide of ethylenediamine is an example of an amide having the structure of the above Formula I. The monocalcium amide of ethylenediamine and the monocalcium amide of diethylene triamine are examples of metal amides having a structure like that of the above Formula II. Lithium amide and sodium amide are examples of metal amides having a structure like that of the above Formula III. Calcium amide is an example of a metal amide having a structure like that of the above Formula IV. The preferred amides for use in the practice of the invention are those of sodium and lithium, lithium amides being the most preferred.

In the practice of the invention said isomerization catalysts are usually employed in a mol ratio of catalyst to cyclotriene being isomerized within the range of 0.05:1 to 20:1, preferably within the range of 0.121 to :1.

The isomerization reaction of the invention is preferably carried out under essentially anhydrous conditions. The presence of small amounts of water can be tolerated. However, the presence of water in the reaction zone decreases the efiiciency of the reaction because water reacts with the metal from which the metal amide catalysts are prepared, and also will react with the metal amides after they have been prepared. Thus it is preferred that the amines and other materials be essentially anhydrous.

The isomerization reaction of the invention is carried out in the presence of an ammonia or an amine solvent or a mixture of said ammonia or amine solvent with another organic solvent. Said solvent or mixtures of solvents should be a solvent for both the isomerization catalyst and the cyclotriene compound being isomerized. Preferred solvents for use in the practice of the invention are the amines mentioned herein. Said ammonia and amine solvents function as proton donors in the isomerization reaction and serve to cause said reaction to go farther toward completion. Thus, the amine solvent used in any particular isomerization reaction of the invention is preferably at least as basic as the amine from which the metal amide catalyst employed in said reaction was prepared. In other words, and generally speaking, if said metal amide catalyst was prepared from a primary amine, then a primary amine solvent should be employed as the solvent media for carrying out the isomerization reaction. If the metal amide catalyst was prepared from a secondary amine, then either a secondary amine or a primary amine can be employed as the solvent media for carrying out the isomerization reaction. Thus, any suitable primary or secondary amine can be employed in the practice of the invention. Generally speaking, the most preferred solvent in any situation is the amine from which the metal amide catalyst was prepared.

Included among the compounds which can be employed as solvents in the practice of the invention are anhydrous ammonia, heterocyclic amines such as piperidine and morpholine, and amines represented by the following formulas wherein each R and R are as defined above in connection with said metal amide catalysts.

Some examples of compounds of the above general formulas which can be employed in the practice of the invention are: ethylenediamine; N,N-dimethylethylenediamine; N,N,N trirnethylethylenediamine; N,N di-npentylethylenediamine; N,N,N'-tri-n-heptylpropane 1,3- diamine; N,N'-di-n-decylpropane 1,2 diamine; N-secbutyldiethylenetriamine; N,N-dimethylcyclohexane-1,4-diamine; N,N,N'-triethylcyclohexane 1,3-diamine; methylamine; diethylamine; di-n-propylamine; n-hexylamine; disec-heptylamine; tert-octylamine', n-decylamine; and the like. It is to be understood that ammonia and the amines named above in connection with the metal amide catalysts also come within the scope of the above general solvent formulas and can be employed as solvents. It is also to be understood that ammonia and the amines set forth above as solvents can also be used to prepare said metal amide catalysts.

The amount of said ammonia or amine solvent employed in the practice of the invention is an amount sufficient to give an ammonia or amine to cyclic triene mol ratio Within the range of about 1:1 to about 20:1, preferably 3:1 to 6:1.

In addition to said ammonia or amine solvent there can also be present in the reaction zone, as a part of the media in which the isomerization reaction is carried out, an additional organic solvent. Said additional organic solvent can be any solvent which is a solvent for the metal amide catalyst and the cyclotriene compound being isomerized and which is chemically inert under the reaction conditions. Included among the suitable additional solvents are the tertiary amines of from 3 to 12 carbon atoms and saturated cyclic and acyclic ethers, including monoethers and polyethers, containing from 2 to 20 carbon atoms per molecule. Examples of suitable additional solvents which can be employed in the practice of the invention include, among others, the following: pyridine, N-methylpiperidine, dimethylaniline, t-rimethylamine, tri-n-butylamine, dicyclohexyl ether, diethyl ether of diethylene glycol, dibutyl ether of ethylene glycol, dimethyl ether of diethylene glycol, N-methylmorpholine, m-dioxane, p-dioxane, tetrahydrofuran, tetarhydropyran, and ethers characterized by the formula R -O-R wherein each R is an alkyl radical containing from 1 to 10 carbon atoms. Examples of ethens characterized by the above formula include, among others, the following: dimethyl ether, diethyl ether; di-nbutyl ether; diisopropyl ether; di-n-hexyl ether; and di-ndecyl ether.

When employed, said additional organic solvent is employed in an amount sufficient to give an organic solvent to ammonia or amine solvent volume ratio within the range of 3:1 to 10:1.

The isomerization reaction of the invention is generally carried out at a temperature within the range of 20 to 200 (3., preferably to C. The reaction time will be governed by such factors as catalyst ratio, and temperature but will generally be in the range of 10 minutes to 24 hours, more generally in the range of 2 to 18 hours. The reaction is carried out under liquid phase conditions, in many instances at atmospheric pressure; however, superatmospheric pressures can be employed to maintain said liquid phase conditions if necessary.

Trans,trans,cis-1,5,9-cyclododecatriene has the following structural formula The isomerization of trans,trans,eis-l,5,9-cyclododecatrlene in accordance with the invention results in the formation of two l2-carbon bicyclic hydrocarbon isomers containing two conjugated carbon to carbon double bonds. These isomers have the following structural formulas designated below as A and B.

For convenience, said compounds will be referred to hereinafter as isomers or compounds A and B.

Either of said above isomers A and B, or mixtures thereof, can be converted by hydrogenation to the novel bicyclo-[5.5.0]-dodecane which has the following structural formula:

Bicyclo-[5.5.0]-dodecane Hydrogenation of said isomer A and/or said isomer B to said bicyclo-[5.5.0]-dodecane can be carried out by dissolving said isomer or isomers in an acidic solvent and contacting the resulting solution with hydrogen in the presence of a hydrogenation catalyst which is suitable for the reduction of olefinic carbon to carbon bonds. Generally speaking, the hydrogenation can be carried out at pressures within the range of about atmospheric to about 1,000 p.s.i.a., and at temperatures within the range of to 200 C. Preferred catalysts are the reduced metals such as platinum, palladium, and nickel, both supported and unsupported varieties. Preferred solvents are the low molecular. weight organic acids such as acetic acid and propionic acid, and low molecular weight alcohols such as methanol and ethanol which have been acidified with an acid such as hydrochloric acid or sulfuric acid.

The novel bicyclodienes and the novel bicyclododecane of the invention have utility in areas where similar compounds such as tetralin' (tetrahydronaphthalene) and Decalin (decahydronaphthalene) are employed. This includes such areasas paint and lacquer solvents and thinners, and liquid absorbent-s for the recovery of vapors of organic compounds such as benzene, ethyl alcohol, ethyl acetate, and acetone. I Saidbicyclic dienes can also be converted by dehydrogenation and isomerization to the corresponding methylbenzosuberanes which have utility as paint and lacquer solvents and thinners, and as musk odorants. The structural formulas for said methylbenzosuberanes are 4-methylbenzosuheraue 3-methylbenzosuberane there is then added, slowly, the cyclotriene compound to be isomerized. The resulting mixture is then maintained at the desired temperature, with stirring, for the desired reaction time. The isomen'zate, comprising bicyclodiene compounds, is then recovered from the resulting reaction mixture.

In another method, the metal amide isomerization catalyst is formed in situ in the presence of an ether solvent. In this method, the ether, e.g., anhydrous n-butyl ether; the metal, e.g., lithium; and the amine, e.g., anhydrous ethylenediamine, are charged to a reaction vessel and refiuxed at a suitable temperature for a suitable length of time to insure complete reaction of said metal with said amine. The cyclotriene compound to be isomerized is then charged to said reaction vessel, the reaction is carried out as described above, and the resulting bicyclodiene compounds are recovered from the resulting reaction mixture.

- In still another method, which is advantageously employed when the metal amide catalyst is prepared by the reaction of the metal amide-with the amine, a slurry of the metal amide, e.g., sodium amide, in a dry low boiling hydrocarbon, e.g., normal pentane, is added to a reaction vessel and a suitable amount of anhydrous amine, e.g., ethylenediamine, is slowly added to said slurry with stirring. The resulting mixture is then stirred at a suitable temperature for a suitable period of time to insure formation of the catalyst. The cyclotriene to be isomerized is then slowly added to the thus formed solution of catalyst, the reaction carried out as above described, and the resulting bicyclodiene compounds recovered from the reaction mixture.

The following examples will serve to further illustrate the invention.

EXAMPLE I Ethylenediamine (98-100%) was purified by refluxing over sodium, with subsequent fractional distillation. To 750 ml. of this purified amine in a 2-liter three-necked flask equipped with stirrer, thermometer, stoppered mol) of 1,5,9-cyclododecatriene (B.P. 96.597 C. at 7- Hg). The triene was added over a period of 8 minutes to the stirred reaction mixture maintained at' 96-98 C. The resulting dark red solution was stirred at 96-98 C. for 1 hour. The solution was then cooled in an ice bath to about room temperature, and the partially solidified mixture was hydrolyzed with 2500 ml. of water. An oil phase separated. The mixture was then extracted with three 400-ml. portions of ether, and the combined ether extracts were dried over anhydrous sodium sulfate. After removal of ether, the product was flash distilled to give 77.1 g. of orange colored liquid boiling over the range from 101? C. at 8.2 mm. Hg to 250 C. at 0.5 Hg. An ether solution of this distillate was extracted with 10% hydrochloric acid and washed with water, then with 5% sodium hydroxide. This ether solution of neutral substances was dried over sodium sulfate.

From the dried ether solution of neutral substances there were obtained by distillation the following four fractions:

Frac Boiling range Grams Refractive tion index (12,)

m.96 C./8.0 mm. Hg 6.0 1. 5105 .0 mm. Hg 7. 7 1. 5225 G./fi.0 mm. 99.5v C./7.6 mm. Hg 31. 2 1. 5253 O./7.6 mm. Hg 5. 2 1. 5268 In addition, there was obtained 2.7 g. of material distilling over the range 87184 C./ 0.23-0.26 mm.

Analysis of fraction 3.Calculated for C I-I C, 88.8; H, 11.2. Found: C, 88.3, 88.0; H, 10.9, 10.8.

The mass spectrum of fraction 3 showed a parent peak at 162. The ultra-violet spectrum indicated the presence of conjugated double bonds. Gas chromatographic analysis revealed the presence of two components in a ratio of approximately 22:78. Infrared analysis indicated the absence of methyl and vinyl groups. Quantitative hydrogenation in acetic acid at room temperature and atoms pheric pressure, with reduced platinum oxide as catalyst, gave a value of 1.96 double bonds per molecule. Hydrogenation of this bicyclic diene mixture in a Parr hydrogenator gave as a product a single saturated substance (as determined by gas chromatography) having the following properties, B.P. 106 C./9.l mrn.-l07.5 C./9.2 mm., n 1.4901. Thus, this is proof that compounds A and B are isomers having the same carbon skeleton.

Analysis of hydrogenated prduct.Calc-ulated for C H C, 86.66; H, 13.33. Found: C, 86.57, 86.63; H, 13.42, 13.36.

EXAMPLE 11 Another run was carried out by the procedure of the preceding example. In this run, the ingredients charged consisted of 100 ml. of anhydrous dibutyl ether, 35 ml. of anhydrous ethylenediamine and 1.7 grams (0.24 mol) of metallic lithium. After refluxing these materials together for four hours, 91.9 grams (0.567 mol) of trans,trans,cis- 1,5,9-cyclododecatriene was added drop-wise. After refluxin-g for 18 hours with stirring, the reaction. mixture was cooled to about room temperature, and a solid separated. The mixture was then added to water and an organic phase separated, the organic phase was extracted with ethyl ether, and the extract was acidified with sulfuric acid to break the emulsion which formed. The combined organic extracts were then washed with acid, followed by a water wash, and were then dried over anhydrous sodium sulfate. The ether was removed by distillation, and the residue was then fractionated. Three of the thirteen fractions from this fractionation were subjected to gas chromatographic analysis. Cut No. 4 boiled at 98 C./8.2 mm. Hg, had a refractive index of 1.5208 @20 C., and amounted to three grams. Cuts 10 and 12 boiled at 98l00 C. at 7.5 mm. Hg and 100 C. at essentially 7.5 Hg respectively, amounted to 32.3 and 5.1 grams respectively, and had respective refractive indices of 1.5256 and 1.5301. Gas chromatographic analyses indicated the presence of cyclododecatriene and two other close boiling materials in the first cut, while the second and third cuts contained only the 2 close boiling materials. The following table lists the contents of these fractionation cuts as determined by said analyses.

Table Weight Weight Weight Cut percent percent percent eyclodocompound compound decatriene B EXAMPLE III Another mm was carried out in which trans,trans,cis- 1,5,9-cyc1ododecatriene was isomerized in the presence of the monolithiuin salt of ethylene-diamine. In this run, n-butylamine was dried by refluxing over metallic sodium, after which the mine was purified by fractional distillation. A 3-neoked flask (500 ml.), fitted with a stirrer, a condenser, an addition funnel and a nitrogen inlet tube was flushed with prepurified nitrogen, after which 100 ml. of said purified amine was charged to the flask. 1.4 grams (0.2 mol) of metallic lithium was cut into small pieces and charged to the flask. The resulting mixture was stirred at refluxing temperature for four hours, after which 15 ml. of anhydrous ethylenediamine was added. The solution turned a deep blue color and hydrogen slowly evolved. The mixture was then allowed to cool and stand overnight, following which it was again heated and stirred and refluxed until the blue color disappeared. At this time, 31.9 grams (0.19 mol) of said cyclododecatriene was added dropwise over a two-hour period while stirring and refluxing the solution. The solution turned red, then darker and finally almost black. Following completion of the addition of cyclododecatriene, the solution was stirred for an additional two hours.

The solution was then cooled to about room temperature, and water was carefully added to hydrolyze. the lithium salt. The aqueous mixture was then extracted with n-pentane, the combined pentane extracts were washed with water, and the water layers were combined. The pentane solution was then washed with 10-20 weight percent H until the extracts were acidic. The organic phase was then washed with sodium bicarbonate solution and with water and then dried over anhydrous sodium sulfate. The pentane was then distilled OE and the bright yellow, clear, residual oil was fractionated at reduced pressure. Results of this fractionation are given in the following table.

Table FRAOTIONATION Boiling Pressure Refractive Cut range, 0 mm. Grams index mercury 1.1 1.5172 6. 2 1. 5179 10.7 1. 5201 5.0 1. 5221 5 3. 2 1. 5251 Residue 0.4

Portions of cuts 2 and 4 from the above fractionation were submitted for analysis by gas chromatography. Both cuts contained the diene products A and B as well as the starting material, cyclododecatriene. A portion of cut 2 was hydrogenated in glacial acetic acid using a reduced platinum oxide catalyst, a temperature of 26 C., a pressure of 740 mm. Hg absolute, and a reaction time of 20 minutes. A total of 61.7 ml. of hydrogen was absorbed, which was calculated to be 2.4-1 double bonds. Thus, said out 2 contained 41 percent by weight cyclododecatriene starting material and 59 percent by weight of the dienes A and B.

EXAMPLE IV A 0.1742 gram sample of out No. 10 from Example 11 was dissolved in glacial acetic acid and then quantitatively hydrogenated over a reduced platinum catalyst at 22.4 C. and at a pressure of 740 millimeters of mercury. During said hydrogenation 49.8 milliliters of hydrogen were absorbed, indicating the presence of 1.96 carbon to carbon double bonds.

EXAMPLE V A run was carried out in which a sample of a mixture of bicyclic dienes A and B was dehydrogenated and isom' erized with a chromia-alumiua catalyst. In this run, 16.4 grams of a mixture of said bicyclic dienes prepared by a procedure essentially identical to those of the previous examples was dehydrogenated and isomerized over a 2.0% chroma-80% alumina catalyst bed at 500 C. The sample of bicyclic dienes before conversion had a boiling point of 99-995 at 7.5 mm. mercury absolute and a refractive index n of 1.5255. Following the conversion, the product was fractionated on a spinning band Podbieln-iak column. The following table gives the results of this fractionation.

Infrared analyses of cuts 2, 3, 4, and 5 were carried out. The spectrum of cut 4 showed bands common to 3- and 4-methylbenzosuberane Since a dehydrogenation and isomerization of cycloheptane yields toluene, then the cyclic dienes are a mixture of isomers, each having a bicyclo [5.5.0] -dodecane skeleton.

Based on the infrared analyses, mass spectrometer analyses, the dehydrogenation and isomerization and all of the measured chemical and physical properties, the two isomers have the formulas A and B shown above.

EXAMPLE VI A series of syntheses were carried out by which methylbenzosuberane was prepared and subsequently compared to the dehydrogenation and isomerization product of Example V.

A mixture of glutaric anhydride (77.5 grams, 0.68 mol) and 350 ml. of toluene was stirred at room temperature in a one-liter, three-necked flask equipped with a stirrer and a condenser. Anhydrous aluminum chloride (178 grams, 1.34 mol) was added in one portion. The resulting reaction was highly exothermic, and HCl gas was rapidly evolved. The mixture turned dark and was stirred at 80-l00 C. for 1.5 hours. After cooling the mixture to C. in an ice bath, a solution which was prepared by mixing 100 ml. of concentrated hydrochloric acid and 100 ml. of water was added slowly. After the acid had been added, the viscous mixture was steam distilled to remove the toluene and to complete the hydrolysis of the aluminum compounds. The resulting mixture was then cooled to 0 C. and filtered by suction. The solid present was then dissolved by boiling in an aqueous solution of sodium carbonate which was prepared by dissolving 100 grams Na CO in 200 ml. water. The undissolved solid which remained was filtered from the hot solution and washed with hot water. Careful acidification of the clear filtrate with hydrochloric acid caused the product to precipitate. The product, p-methylbenzoylbutyric acid, was filtered and air dried overnight. The total weight of yellow solid which was recovered was 113 grams, representing an 80.7% yield. After recrystallization from benzene, the product melted at 152-4 C.

The p-methylbenzoylbutyric acid which was prepared by the above-described procedure was converted to 5-ptolylvaleric acid in the following manner. Thirty-three grams (0.16 mol) of p-methylbenzoylbutyric acid, 25.6 grams (0.64 mol) of sodium hydroxide and 25 ml. of hydrazine hydrate in 150 ml. of triethylene glycol was refluxed for one hour in a 300 round-bottomed flask equipped with a condenser. The condenser was then removed, and the solution was distilled until the pot temperature reached 195 C. The condenser was then replaced, and the solution was thenrefluxed an additional three hours. Upon cooling to room temperature, the contents of the flask solidified. The entire mixture was dissolved in water, and the solution was carefully acidified with hydrochloric acid. A light yellow solid product precipitated from the solution, and atter filtration, was pressed dry. The air dried product, 5-p-tolylvaleric acid, was dissolved in cyclohexane, and the excess water was separated off. Azeotropic distillation removed the last traces of water. Upon cooling the cyclohexane solution, the product crystallized out. An additional 3.9 grams was recovered from the mother liquors. A total yield of 93.1% of 5-p-tolylvaleric acid, melting point 78-9 C. was obtained. I r

The 5-p-to1ylva1eric acid was then n'n-g closed to form 5H-2-methyl-5,6,7,8-tetrahydro-9 benzocycloheptanone in the following manner. Polyphosphoric acid was prepared by dissolving 306 grams of P 0 in 195 cc. of by weight phosphoric acid and then heating the resulting mixture on a steam bath for 3 hours with occasional stirring. This polyphosphoric acid was then used in the ring closure synthesis step, this step being essentially the same as that outlined by C. L. Anderson, et al., Journal of American Chemical Society, 77, 598 (1955). The polyphosphoric acid as prepared above was charged to a 500 ml. Erlenmeyer flask, and to this acid was added 24.7 grams (0.128 inol) of the 5-p-tolylvaleric acid which was prepared as described above. The resulting mixture was then heated on a steam bath for 2 hours, aflter which the reaction mixture was allowed to stand overnight (14 hours) at room temperature. The mixture was then poured onto crushed ice, and the resulting product was extracted with pentane. The combined pentaue extracts were washed with. an aqueous sodium carbonate solution, after which the hydrocarbon phase was dried over anhydrous sodium sulfate. The pentane was then stripped ofi, leaving a light yellow oil (21.2 grams). Thisyellow oil was then fractionated at reduced pressure. Results of the fractionation were as follows:

The total yield was 19.5 grams, representing an 87.4% yield. The measured density of cut 2 at 20 C. was 1.0290. The semicarbazone of cut 1 melted at 197.5- 8 C.

The 5H 2 methyl 5,6,7,8 tetrahydro- 9 benzocycloheptanone was then converted to 4-methy-lbenzosu'berane bythe following procedure. A solution consisting of 15.4 grams of cuts 1 and 3 from the above fractionation, 10.2 grams of sodium hydroxide and 15 ml. of hydrazine hydrate in 70 ml. of triethylene glycol was refluxed 'for one hour in a 300 ml. round-bottomed flask equipped with a condenser. 'Ihe condenser was then replaced by a vapor line passing to a receiver. The solution was then distilled, and the condensate collected, until the pot temperature reached C. The solution was then refluxed for an additional 2.5 hours, aflter which the solution was allowed to cool to room temperature. Both the collected condensate and the remaining mixture in the pot were poured into water and extracted with pentane. The combined extracts were then dried over anhydrous sodium sulfate, after which the pentane distilled off. Fractionation at reduced pressure gave 2 cuts. Cut 1 boiled at 98 C. at 6.1 mm. mercury absolute pressure, and amounted to 8.8 grams (9.3 ml.). cut had a refractive index n of 1.5366. The second cut boiled at 98 C. at 6.1-1.0 mm. mercury absolute pressure, and amounted to 3.7 grams (4.0 ml.). This material had a refractive index of 1.5368 (11 The total recovered amount, 11.5 grams, represents a yield of 81%.

The infrared spectrum of cut 1 was identical to that of the spectrum reportedin the literature for 4-methylbenzosuberane. The retention time of cut 1 in gas chromatography, was identical to the retention time of the major component in the dehydrogenation and isomerization mixture of Example V. Both the infrared spectrum and gas chromatographic results confirm the formation of 4-me'thyl benzosuberane when the bicyclic diene mixture is dehydrogenated and isomerized as described in Example V.

, The compounds synthesized above were subjected to elemental analyses. The results were:

S-ptqlylvaleric acid-Calculated for C H O z C, 75.0 wt. percent; H, 8.3 wt. percent. Found: C, 75.0 wt. percent; H, 8.5 wt percent.

Cut 2 of the benzocycloheptanone.-Calculated for C H O: C, 82.8 wt. percent; H, 8.0 wt. percent. Found: C, 82.7 wt. percent; H, 8.4 wt. percent.

Semicarbazone of cut 2 of the benzocycloheptanone.-- Calculated for C H N O: C, 67.5 percent; H, 7.4 wt. percent. Found: C, 67.3 wt. percent; H, 7.9 wt. percent.

4-methyl-benzdsuberane-Oalculated for C H C, 89.9 wt. percent; H, 10.1 wt. percent. Found: C, 89.5 wt. percent; H, 10.0 wt. percent.

EXAMPLE VII Another run was carried out in which trans,trans,cis-

1,5,9cyclododecatriene was isomerized by the procedure of Example I. In this run, 31.6 grams (0.198 mol) of said cyclododecatriene was added drop wise over a two hour period to a mixture of 100 m1. of dim-butyl ether and 25 ml. of anhydrous ethylenediamine to which had been added 1.4 gram (0.2 mol) of lithium metal at 108 C., followed by stirring at 108 C. until all of the lithium had reacted. The temperature of the reaction mixture during addition of the cyclododecatriene was 106 C.

After the drop wise addition of the cyclododecatriene had been completed, the resulting mixture was stirred at reflux for 3 hours, after which it was allowed to cool to room temperature and stand overnight (15 hours) under a nitrogen blanket. At the end of this time, the mixture was again heated to reflux (106 C.) and maintained at this temperature of 6.5 hours. The mixture was then cooled to about room temperature and water added. The product was then worked up as in Example I. The organic material was distilled at reduced pressure and a cut which boiled at 100.5-101.5 C. 8.5 mm. Hg absolute pressure was employed in the following manner. A solution of 12.7 grams of the isomerized material from the above fractionation cut and 9.8 I grams of maleic anhydride in 50 ml. of benzene was refluxed for 15 hours in a round-bottomed flask equipped with a condenser and a drying tube. After the benzene solution was cooled to room temperature, 50 ml. of 20% by weight aqueous sodium hydroxide was added to the solution, and the resulting mixture was shaken. A solid separated, and the slurry was then poured into a 500 ml. flask. Three hundred milliliters of n-pentane and 100 ml. of water were then added to the mixture, and the resulting mixture was stirred with a magnetic stirring bar. After three hours of stirring, the mixture was filtered.

The, solid was actually an emulsion which could be partially broken with water. The entire solid mixture was then placed in. a separatory funnel and extracted with water. After each period of shaking, the mixture had to stand for about 15 minutes before the water layer would separate. The pentane-benzene layer was an emulsion. After 5 extractions with 100 ml. portions of water, the fifth mixture was allowed to settle, ancl most of the water was drainedoff. The remaining emulsion was dried over a large excess of anhydrous sodium sulfate untilthe hydrocarbon layer clearly separated.

' Thepen'tane and'benzene were then distilled off, and the .residue'was then distilled under reduced pressure. A

12 total of 4.0 grams of colorless liquid was obtained, B.P. 96.597 C. 7.5 mm. Hg absolute pressure. The refractive index of this material was n '=1.5255.

Gas chromatographic analysis of this material showed the presence of both isomers, the mixture containing 77 wt. percent of isomer A and 20 wt. percent of isomer B. Prior to treatment with maleic anhydride, the weight ratio of isomer B to isomer A was approximately 2:1.

While this run does not show complete separation of the isomers, it does show that mixtures can be concen trated with respect to one isomer by treatment with maleic anhydride.

EXAMPLE VIII denser was employed. The amide was generated in situ in the following manner.

A slurry of 14.7 grams (0.377 mol) of sodium amide in 50 ml. of dry n-pentane was charged to the flask and 90 ml. of anhydrous ethylenediamine which had been previously purified by refluxing with sodium, followed by fractionation from sodium, was then added to the slurry while stirring over a period of 5 minutes. The mixture turned deep purple in color and ammonia was slowly evolved. Upon heatingthe stirred mixture to reflux, ammonia was evolved at a moderate rate.

The pentane was then removed by passing nitrogen.

through the flask. The mixture was then stirred at approximately 95 C. for two hours at which time 42.5 grams of said cyclododecatriene (0.262 mol) wasadded over a 15 minute period. The resulting dark mixture was then stirred at reflux for 45 minutes. After cooling the mixture to room temperature, water was cautiously added to the mixture while stirring. The resulting mixture was then extracted with pentane, following which the combined extracts were washed with water. The organic layer from the extraction was then washed with saturated aqueous NaHCO solution, then with water, after which it was dried over sodium sulfate.

The pentane was then distilled off, and the residue, a yellow oil amounting to 14.3 grams was then fractionated at reduced pressure. The results of this fractionation were as follows:

Total Infrared spectra ofcuts 2 and 3 were almost identical to the spectra of the bicyclic dienes from the isomerization with lithium amide catalysts (Example I).

This run shows that amides of alkali metals other than lithium can be employed in the isomerization process of this invention.

EXAMPLE IX amined had the following analyses by gas chromatography.

The following results Were obtained from the nuclear magnetic resonance spectra.

The ratio of aliphatic protons to vinylic protons for the sample from Example II was 7.321, while the ratio for the sample from Example VII was 8.3:1. Since the isomers both have the formula C H the possible ratios of aliphatic to vinylic protons would be 17:1, 16:2, 15:3, 14:4, which reduces to 17:1, 8:1, :1, and 35:1. Thus, the experimental values are in agreement with 8:1, and there are, therefore, 2 vinylic protons in each of both isomers.

As shown in Examples I-V, both isomers are bicyclo- [5.5.0] dodecadienes. The fact that the nuclear magnetic spectra show 2 ,vinylic protons in each isomer is further evidence that the two dienes are simple ringfused structures since this eliminates all bridged compounds. It is not possible to have only 2 vinylic protons in such bridged structures without locating both double bonds at the bridgehead carbon atoms, a situation which has been shown to be highly improbable (Bredts Rule). See Advanced Organic Chemistry, G. W. Wheland, Second edition, John Wiley and Sons, Inc., New York (1954). Thus, the bicyclic ring systems which are possible are (5,9), (6,8), (7,7), (10,4), and (11,3). The latter two are extremely unlikely.

Higher resolution of the vinyl proton region of the spectrum Was also carried out. The sample from Example'II, substantially all isomer B, revealed a sextuplet which is consistent with a methylene group adjacent to a double bond with 2 vinyl protons, i.e.

--CH2-(IJ=CIE Thus, in order to place the second double bond in conjugation with the double bond and not increase the number of vinyl protons (since a total of two are present), it is necessary for this second double bond to be located between the two ring fusion carbons. Thus, the double bonds in isomer B are located as follows:

i H H zhn (C M tion and isomerization of the isomers produces methylbenzosuberanes, thus proving that the rings each contain seven carbons, and the ring system is [5.5.0], the structure for isomer B is thus:

Bicyclo [5.5.0] -A ,2-dodecadiene The vinyl region of the spectrum of the sample from Example VII, predominantly isomer A, was much different from that of isomer B in that a triplet was observed. This type of spectrum is consistent with vinyl protons symmetrically located within the molecule.

Considering these results with the analytical results given in the other examples, particularly the maleic anhydride adduct in Example VII, it is concluded that the structure of isomer A is H, H, o-o

Bicyclo [5.5.0]-1,7-dodecadiene While the invention has been described above with particular reference to the isomerization of trans,trans, cis-l,5',9-cyclododecat1iene it is also within the scope of the invention to isomerize derivatives and homologues of said cyclotriene, particularly those derivatives having various substituents, such as alkyl radicals, attached to ring carbon atoms. 'It is also within the scope of the invention to isomerize the cyclic trimers of isoprene and piperylene (1,3-pentadiene). The trimers of both of said dienes will be trimethylcyclododecatrienes. In the case of the isoprene trimer, each of the three methyl groups will be attached to a carbon which is attached to a carbon to carbon double bond. The piperylene trimer will have methyl groups attached to carbon atoms which are attached to saturated bonds.

Although the isomerization process has been described as a batch operation, it will be apparent to those skilled in the art that a continuous system can be employed without deviating from the inventive concept disclosed herein.

While certain embodiments of the invention have been described for illustrative purposes, the invention obvious ly is not limited thereto. Various other modifications will be apparent to those skilled in the art in view of the above disclosure. lSuch modifications are within the spirit and scope of the invention.

We claim:

1. A bicyclo hydrocarbon selected from the group consisting of bicyclo-[5.5.0]-1,7-dodecadiene and bicyclo- [5.5.0]-A -",2-diodecadiene.

2. Bicyclo- [5 .5 .0] 1 ,7-dodecadiene.

3. Bicyclo-[5.5.0]-A ,2-dodecadiene;

4. A process for isomerizing a cyclotriene hydrocarbon containing from 12 to 15 carbon atoms per molecule to a bicyclodiene hydrocarbon containing the same number of carbon atoms and hydrogen atoms as said starting cyclotriene hydrocarbon, which method comprises: contacting said cyclotriene under isomerizing conditions 'with an isomerization catalyst selected from the group consisting of alkali metal amides and alkaline earth metal amides in the presence of a solvent. selected from the group consisting of ammonia and suitable primary and secondary amines which is a solvent for both said cyclotriene and said isomerization catalyst; and recovering said bicyclodiene hydrocarbon.

5. A process for isomerizing trans, trans, cis-1,5,9. cyclododecatriene to a bicyclo-[5 .5 .0]-dodecadiene hydrocarbon which process comprises; contacting said cyclododecatriene under isomerizing conditions with an isomerization catalyst selected from the group consisting of alkali metal amides and alkaline earth metal amides in the presence of a solvent selected from the group consisting of ammonia and suitable primary and secondary amines which is a solvent for both said cyclododecatriene and said isomerization catalyst; and recovering said dodecadiene hydrocarbon.

6. A process for the preparation of a bicyclo dodecadiene hydrocarbon selected from the group consisting of bicyclo [5.5.0 ]-l,7-dodecadiene, bicyclo-[5.5.0]-A ,2- dodecadiene, and mixtures thereof, which process comprises: contacting trans, trans, cis-l;5,9-cyclododecatriene under isomerizing conditions with an isomerization catalyst selected from the group consisting of alkali metal amides and alkaline earth metal amides in the presence of a solvent selected from the group consisting of ammonia and suitable primary and secondary amines which is a solvent for both said cyclododecatriene and said isomerization catalyst; and recovering said dodecadiene hydrocarbon.

7. The process of claim 6 wherein said dodecadieneis bicyclo-[5.5.0]-1,7-dodecadiene.

8. The process of claim 7 wherein: said cyclododecatriene is contacted with said isomerization catalyst at a temperature within the range of 20 to 350 C., for a period of time within the range of 10 minutes to 24 hours; said isomerization catalyst is present in an amount sufiicient to give a catalyst to cyclododecatriene mol ratio within the range of 0.05:1 to 20:1; and said solvent is present in a mol ratio of solvent to said cyclododecatriene within the range of about 1:1 to about 20:1.

9. The process of claim 6 wherein said dodecadiene is bicyolo- .5 .0] -A ,2-dodecadiene.

10. The process of claim 9 wherein said cyclododecatriene is contacted with said isomerization catalyst at a temperature within the range of 20 to 350 C., for a period of time within the range of 10 minutes to 24 hours; said isomerization catalyst is present in an amount suflicient to give a catalyst to cyclododecatriene mol ratio within the range of 0.05:1 to :1; and said solvent is present in a mol ratio of solvent to said cyclododecatriene within the range of about 1:1 to about 20:1.

11. The process of claim 6 wherein said dodecadiene hydrocarbon is a mixture of bicyclo-[5.5.0]-1,7-dodecadiene and bicyclo- [5.5 .0] -A ,2-dodecadiene.

12. The process of claim 11 wherein said cyclododecatriene is contacted with said isomerization catalyst at a temperature within the range of 20 to 350 C., for a period of time within the range of 10 minutes to 24 hours; said isomerization catalyst is present in an amount sufiicient to give a catalyst to cyclododecatriene mol ratio within the range of 0.05:1 to 20:1; and said solvent is present in a mol ratio of solvent to said cyclododecatriene within the range of about 1:1 to about 20:1.

13. A process for isomerizing trans, trans, cis-1,5,9- cyclododecatriene to a bicyclo-[5.5.0] -dodecatriene hydrocarbon which process comprises: contacting said cyclododecatriene under isomerizing conditions with an isomerization catalyst selected from the group consisting of a1- kali metal amides and alkaline earth metal amides in the presence of a rfirst organic solvent which is a solvent for both said cyclododecatriene and said catalyst and which is chemically inert under said isomerizing conditions, and also in the presence of a second solvent selected from the group consisting of ammonia and suitable primary and secondaryamines which is also a solvent for both said cyclododecatriene and said isomerization catalyst; and recovering said dodecadiene hydrocarbon.

14. A process for isomerizing trans, trans, ci s-1,5,9- cyclododecatriene to a bicyclo-[5.5.0]-dodecadiene hydrocarbon which process comprises: contacting said cyclododecatriene under isomerizing conditions with an isomerization catalyst selected from the group consisting of alkali metal amides and alkaline earth metal amides in the presence of an ether solvent which is a solvent for both said cyclododecatriene and said catalyst, and also in the presence of a solvent selected from the group consisting of ammonia and suitable primary and secondary amines which is also a solvent for both said cyclododecatriene and said isomerization catalyst; and recovering said dodecadiene hydrocarbon.

15. A process for the preparation of a bicyclo-[5.5.0]-

,dodecadiene hydrocarbon selected from the group con- 16 sisting of bicyclo- [5 .5 .0] -1 ,7-dodecadiene, bicyclo-[ 5.5.0]- A 'LZ-dodecadiene, and mixtures thereof, which process comprises contacting trans, trans, cis-1,5,9-cyclododecatriene, at a temperature within the range of 20 to 350 C., for a period of time within the range of'10 minutes to 24 hours, with an isomerization catalyst present in an amount suflicient to give a catalyst to cyclododecatriene mol ratio within the range of 0.05:1 to 20:1, in the presence of an essentially anhydrous solvent which is a solvent for both said catalyst and said cyolododecatriene and which is present in a mol ratio of solvent to said cyclododecatriene within the range of about 1:1 to about 20:1, and recovering -said bicyclo-[5.5.01-dodecadiene hydrocarbon from the resulting reaction mixture; said isomerization catalyst being selected from the group consisting of alkali metal and alkaline earth metal amides characterized by the following structural formulas R R i R M+ ass; M Ma; Mp ,1

R l R z i and l 10 carbon atoms, and (c) F N u L Jy radicals wherein R is as defined above, -R is an alkyle'ne radical containing from 2 to '3 carbon atoms, y is an integer of from 1 to 2, and wherein when R is a cycloalkylene radical, only one amino nitrogen atom is attaohed to any one ring carbon atom; and said solvent being selected trom the group consisting of ammonia, piperidine, morpholine, and amines characterized by the following formulas R H H wherein each R, and R, are as defined above.

16. The process of claim 15 wherein said isomerization catalyst is the monoamide of sodium and ethylene diarnine and said solvent is ethylene diamine.

17. A process for the preparation of a bicyclo-[5.5.0]- dodeoadiene hydrocarbon selected from the group consisting of bicyclo [5.5.0] 1,7 dodecadiene, bicyclo- [5.5.0]-A ,2d0decadiene, and mixtures thereof, which process comprises: contacting trans,tr-ans,cis-1,5,9 :yclododecatriene at a temperature within the range or 20 to 350 C., for a period of time within the range of 10 minutes to 24 hours, with an isomerization catalyst present in an amount suflicient to 'give a catalyst to cyclododecatriene mol ratio within the range of 0.05:1 to 20:1, in the presence of an essentially anhydrous first solvent which is a solvent for both said catalyst and said cyclododecatriene and which is present in a mol ratio of said first solvent to said cyclododecatriene within the range of about 1:1 to about 20: 1, and also in the presence of an essentially anhydrous second solvent which is also a solvent for both said catalyst and said cyclododecatriene and which is present in an amount suflicient to give a second solvent to first solvent volume ratio within the range of 3:1 to 10:1; and recovering said bicyclo- [5.5. O]-dodecadiene hydrocarbon from the resulting reaction mixture; said isomerization catalyst being selected 1 7 from the group consisting of alkali metal and alkaline earth metal amides characterized by the following structural formulas wherein: M is an alkali metal selected from the group consisting of sodium, potassium, lithium, rubidium, and cesium; M is an alkaline earth metal selected from the group consisting of calcium, strontium and barium; each R is selected from the group consisting of a hydrogen atom and alkyl radicals containing from 1 to carbon atoms; and R is selected from the group consisting of (a) alkylene radicals containing from 2 to 3 carbon atoms, (b) cycloalkylene radicals containing from 6 to 10 carbon atoms, and (c) radicals wherein R is as defined above, R" is an alkylene radical containing from 2 to 3 carbon atoms, y is an integer of from 1 to 2, and wherein when R is a cycloalkylene radical, only one amino nitrogen atom is attached to any one ring carbon atom; said first solvent being selected from the group consisting of ammonia, piperidine, morpholine, and amines characterized by the following formulas R H H R-I I- R and R-IL R wherein each R, and R, are as defined above; and said second solvent being selected from the group consisting of tertiary amines containing from 3 to 12 carbon atoms, and saturated cylic and acyclic ethers containing from 2 to carbon atoms per molecule.

18. A process for the preparation of a bicyclo dodecadiene hydrocarbon selected from the group consisting of bicyclo-[5.5.0]-1,7-dodecadiene, bicyclo-[5.5.0]-A ,2- dodecadiene, and mixtures thereof, which process comprises: forming a solution of monolithium amide isomerization catalyst by reacting lithium metal with an excess of essentially anhydrous ethylenediamine; adding trans,trans,cis 1,5,9 cyclododecatrlene to said solution in an amount sufficient to give a catalyst to triene mol ratio within the range of about 0.1:1 to about 10:1 and a mol ratio of ethylenediamine to said cyclotriene within 18 the range of about 1:1 to about 20:1, contacting said triene with said catalyst solution of a temperature within the rangeof about to about C. for a period of time within the range of about 10 minutes to about 24 hours; and recovering said bicyclo dodecadiene from the resulting reaction mixture.

19. A process for the preparation of a bicyclo dodecadiene hydrocarbon selected from the group consisting of bicyclo- 5 .5 .0] 1 ,7-dodecadiene, bicyclo- [5 .5 :0] -A ",2- dodecadiene, and mixtures thereof, which process comprises: forming a solution of monolithium amide isomerization catalyst by reacting lithium metal with an excess of essentially anhydrous ethylenediamine in the presence of an essentially anhydrous ether solvent; adding trans, trans, cis-1,5,9-cyclododecatriene to said solution in an amount sufiicient to give a catalyst to cyclododecatriene mol ratio within the range of about 0.1:1 to 10:1 and a mol ratio of ethylenediarnine to said cyclododecatriene within the range of about 1:1 to about 20:1; said ether solvent being present in an amount sufiicient to give an ether to amine volume ratio within the range of 3:1 to 10:1; contacting said triene with said catalyst in the resulting solution at a temperature within the range of about '90 to about 150 C. for a period of time Within the range of about 10 minutes to about 24 hours; and recovering said bicyclo dodecadiene from the resulting reaction mixture; said ether solvent being selected from the group consisting of saturated cyclic and acyclic ethers containing from 2 to 20 carbon atoms per molecule.

20. A process for the preparation of bicyclo-[5.5.0]- dodecane, which process comprises: hydrogenating a bicyclo dodecadiene selected from the group consisting of bicyclo-[5.5.0]-l,7-dodecadiene, bicyclo-[5.5.O]-A ,2- dodecadiene, and mixtures thereof, in the presence of a reduced metal hydrogenation catalyst at a temperature within the range of 0 to 200 C. and under a pressure within the range of atmospheric to 1000 p.s.i.a.; and recovering said dodecane.

21. The process of claim 20 wherein said bicyclo dodecadiene is bicyclo- [5.5.0] -1,7-dodecadiene.

22. The process of claim 20 wherein said bicyclo dodecadiene is bicyclo- [5.5.0] -A ,2-.dodecadiene.

23. The process of claim 20 wherein said bicyclododecadiene is a mixture of bicyclo-[5.5.0]-l,7-dodecadiene and bicyclo- [5.5.0] -A ,2-dodecadiene.

References Cited in the file of this patent Buchi et al.: Helvetica Chemica Acta (Switzerland), vol. 32, pp. 538-544 (1949) (in German). Abstracted in Chemical Abstracts, vol. 43, page 5375.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 OO9 OOl November 14 1961 Donald L Grain et a1.

It is hereb; certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 14 line 48 for "diodecadiene" read dodecadiene -3 column 15 line 418 for 'dodeeatriene" read dodecadiene Signed and sealed this 1st day of May 1962',

(SEAL) Attest:

DAVID L. LADD ERNEST W, SYIIHDER Commissioner of Patents 'A ttesting Officer 

1. A BICYCLO HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF BICYCLO-(5.5.0)-1,7-DODECADIENE AND BICYCLO(5.5.0)-$1,7,2-DIODECADIENE.
 4. A PROCESS FOR ISOMERIZING A CYCLOTRIENE HYDROCARBON CONTAINING FROM 12 TO 15 CARBON ATOMS PER MOLECULE TO A BICYCLODIENE HYDROCARBON CONTAINING THE SAME NUMBER OF CARBON ATOMS AND HYDROGEN ATOMS AS SAID STARTING CYCLOTRIENE HYDROCARBON, WHICH METHOD COMPRISES: CONTACTING SAID CYCLOTRIENE UNDER ISOMERIZING CONDITIONS WITH AN ISOMERIZATION CATALYST SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL AMIDES AND ALKALINE EARTH METAL AMIDES IN THE PRESENCE OF A SOLVENT SELECTED FROM THE GROUP CONSISTING OF AMMONIA AND SUITABLE PRIMARY AND SECONDARY AMINES WHICH IS A SOLVENT FOR BOTH SAID CYCLOTRIENE AND SAID ISOMERIZATION CATALYST, AND RECOVERING SAID BICYCLODIENE HYDROCARBON. 